With time running out for Athens to reach a reform-for-aid deal with its international creditors, Greek Prime Minister Alexis Tsipras arrived in St Petersburg earlier on Thursday for talks with Russian President Vladimir Putin and other officials.

"There have been no requests (for help from Greece)," Storchak told Reuters at the St Petersburg International Economic Forum. "There are no resources (in our budget to provide money)."

Storchak said Russia was interested in Greece resolving its financial problems and normalizing relations with its partners, adding that Moscow did not want any "escalation of tensions".

"When the measures needed to solve (Greece's) current problems are on such a huge scale, no one country in the world can do this on its own. Only joint efforts of many countries at once can help."

German Chancellor Angela Merkel said on Thursday a deal between Greece and its creditors was still possible to prevent a debt default by Athens and its possible exit from the euro zone, but she said greater political will was needed.